Eichornia crassipes (Mart.) Solms
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
An NAS report (1976) explores the potential conversion of water weeds to
fertilizer, food, fuel, paper, fiber, and energy. Subsistence farmers in
Bangladesh face disaster when rafts of water hyacinth weighing up to 300 MT/ha
float over their rice paddies. As the floods recede, the weeds remain on the
germinating rice, thus killing it. Bengalis have learned to use the enemy for
fuel and fertilizer. Engineers have estimated that the Panama Canal would be
impassable within three years without continuous aquatic weed control measures.
Aquatic weeds may require absorbent materials such as dried industrial mill
by-products to ferment good silage. In Florida, dried citrus pulp and molasses
have been added to water hyacinth residues as sources of carbohydrate and
absorbent. Byproducts of the rice, grain, and sugarcane milling industries and
waste cassava are potential substitutes. Edible water spinach (Ipomoea
aquatica) already occurs intermingled with water hyacinth in Panama (Curtis
and Duke, 1982). Through an anaerobic fermentation process, polluted hyacinths
can be converted to the natural gas methane--a costly process that may become
more economical as supplies of underground natural gas are depleted. Dried and
cleansed plants, can be used as fertilizer, poultry feed, additives to
cattle-feed, and plant mulch. Eventually, living aquatic plants might serve
aboard long-distance manned spacecraft, absorbing wastes and converting carbon
dioxide to oxygen, then being themselves converted into food. "I fully intend
to solve a major pollution problem, a major energy problem, a major food
problem, and a major fertilizer problem," declares Wolverton (as quoted in
BioScience Vol. 26, No. 3, March 1976). And lowly water hyacinths have given
him a head start. Wolverton and McDonald (1981) note "cultivation of higher
plants for use in wastewater treatment, and incorporation of these plants into
a system where the biomass is harvested for fuel production is economically
appealing at the present time. Since this biomass is a by-product of
wastewater treatment, it has a positive environmental impact, and thus poses no
threat as competitor to food, feed, or fiber-producing plants." The plant has
been used for cigar wrappers and, as a mushroom growing medium (Holm et al.,
1977) but seems unsatisfactory for paper and pulp. Said to be used as a
carotene-rich table vegetable in Formosa. Javanese sometimes cook and eat the
green parts and inflorescence. In Africa, fresh plants are used as cushions in
canoes and to plug holes in charcoal sacks. Chinese cultivate the water
hyacinth in fish ponds as pig fodder, the pig manure recycled into the fish
pond. Fish taken from the manured pond are transferred to clean tanks and fed
more wholesome food before human consumption. In India, where yields of 150 MT
fodder/ha/yr are reported, the water hyacinth is fed to water buffalos (ca 7
kg/day fresh fodder) which are said to exhibit 10-15% milk increases (but the
milk is more watery).
It is strange to me that this pantropical weed has acquired such a small
medicinal folklore. In Kedah (Java), the flowers are used for medicating the
skin of horses. Duke and Wain (1981) report only that the species is "tonic."
Fresh plant contains 95.5% moisture, 0.04% N, 1.0% ash, 0.06% P2O5, 0.20% K2O,
3.5% organic matter. On a zero-moisture basis, it is 75.8% organic matter,
1.5% N, and 24.2% ash. The ash contains 28.7% K2O, 1.8% Na2O, 12.8% CaO, 21.0%
Cl, and 7.0% P2O5. The CP contains, per 100 g, 0.72 g methionine, 4.72 g
phenylalanine, 4.32 g threonine, 5.34 g lysine, 4.32 g isoleucine, 0.27 g
valine, and 7.2 g leucine (Matai and Bagchi, 1980). Water hyacinth roots
naturally absorb pollutants, including such toxic chemicals as lead, mercury,
and strontium 90 (as well as some organic compounds believed to be
carcinogenic) in concentrations 10,000 times that in the surrounding water
(BioScience 26(3): 224. 1976). Nutritive values are tabulated by Gohl (1981)
in the following table:
Eating the plant, reported to contain HCN, alkaloid, and triterpenoid, may
induce itching (Perry, 1980). Fresh plants contain prickly crystals. Plants
sprayed with 2,4-D may accumulate lethal doses of nitrates (Gohl, 1981).
Perennial aquatic herb; rhizome and stems normally floating,rooting at the
nodes, with long black pendant roots. Leaves usually with inflated spongy
petioles, the leaf blades circular to reniform, 4-12 cm wide. Inflorescence a
contracted panicle, 4-15 cm long, with several flowers; perianth lilac, bluish-
purple, or white, the upper lobe bearing a violet blotch with a yellow center.
Stamens 6; stalk of the inflorescence soon becoming goose-necked, forcing the
dead flowers under the water; capsule dehiscent, surrounded by the perianth,
membraneous, many-seeded (Reed, 1970). (Ag. Handbook 366)
Reported from the South American Center Of Diversity, waterhyacinth, or cvs
thereof, is reported to tolerate grazing and waterlogging. (2n = 32)
Native to Brazil, now growing in most tropical and subtropical countries. Holm
et al (1979) list more than 50 countries in which waterhyacinth is weed.
Estimated to range from Tropical Desert to Rain through Subtropical or Warm
Temperate Desert to Rain Forest Life Zones, waterhyacinth is reported to
tolerate annual precipitation of 8.2 to 27.0 dm (mean of 8 cases = 15.8),
annual temperature of 21.1 to 27.2°C (mean of 5 cases = 24.9), and estimated
pH of 5.0 to 7.5. Leaves are killed by frost, and plants cannot tolerate water
Apparently harvesting is more critical than cultivation. Seeds can tolerate
submersion or desication for 15 years and still germinate. Scarification, but
not light, may be required for germination. Recently there has been interest
in cultivating waterhyacinths for waste water treatment.
Rafts of waterhyacinth have been harvested manually, with specially equipped
dredges, rakes, and have been mechanically piled by crushers, elevators,
grapplers, rollers, sawboats, etc. Rafts have even been towed to sea; where
the salt water kills it. Wilted water hyacinth, mixed with earth, cow dung,
and woodashes in the Chinese compost fashion, can yield compost in two months.
Although yields are incredible, so are the costs of removal or attempted
eradication of this water weed. Standing crops have been estimated to produce
100-120 MT/ha/yr. Under ideal conditions, each plant can produce 248 offspring
in 90 days (Matai and Bagchi, 1980). Murry and Benemann (1981) compare various
standing crops of waterhyacinth, rounded off to 13-15 MT/ha in Louisiana, 6-21
in Alabama, 30 in Iowa, 11 in Mississippi. Perhaps more meaningful were their
productivity figures, ca 13-15 in Louisiana, 5-28 in Alabama, 4-29 in Iowa,
5-54 in Florida, up to 88 in Mississippi on sewage effluent. In Florida, an
upper limit on the value was set at $6.42 per wet ton, when used in a compost
blend. Mara (1976) doubted that the value of the waterhyacinth would cover the
cost of transporting and spreading as a soil amendment. Further, if all the
cattle in Florida were fed year round, that would require <3% of the
According to the phytomass files (Duke, 1981), annual productivity ranges from
15-30 MT/ha. Holm et al (1977) suggest that a floating mat of medium sized
plants may contain 2,000,000 plants/ha weighing 270-400 MT wet (15-20 MT DM).
Benemann (1981) concludes, however, that in Southern US, productivity should be
80 MT/ha DM compared to 40-60 for green algae and marsh plants. Comparing DM
yields of more than 20 genera representing many life forms in Florida, Smith
and Dowd (1981) gave the highest figure, 88 MT/ha/yr to waterhyacinth, followed
by Hydrocotyle at 58, napier grass at 57, and sugarcane at 54. While not
exactly representing head-on trials, the following Table, synthesized from
several produced by Smith and Dowd (1981) suggests that waterhyacinth is more
productive of biomass than other items tabulated.
|As % of dry matter |
|DM ||CP ||CF ||Ash ||EE ||NFE ||Ca ||P |
|Fresh, green part, India||5.9 ||13.1 ||18.2||15.3|| 1.3 ||52.1 ||2.16 ||0.41 |
|Fresh, green part, Philippines ||7.8 ||12.8 ||24.6 ||11.9 ||3.3 ||47.4 |
|Hay, India || ||11.6 ||24.2 ||17.8 ||0.7 ||45.7 ||2.19 ||0.64 |
|Silage, Philippines ||10.1 ||9.9 ||19.7 ||19.0 ||1.5 ||49.9 |
|Haylage, India ||33.5 ||11.4 ||24.5 ||20.1 ||1.4 ||42.6 ||2.02 ||0.23 |
|Haylage with 2% salt, India ||46.8 ||13.9 ||17.4 ||18.9 ||1.5 ||48.3 ||1.70|| 0.21 |
|Dried root, Sudan ||92.7 ||5.8 ||20.5 ||3.7 ||0.9 ||69.1 |
|Digestibility (%) |
|Animal ||CP ||CF ||EE ||NFE ||ME |
|Hay ||Zebu ||37.9 ||62.1|| 53.4 ||60.4 ||1.76 |
|Silage ||Sheep||56.1 ||57.1 ||76.2 ||78.5 ||2.15 |
Once harvested and dried, the dry matter of the water hyacinth is roughly
equivalent to the dry matter of our other species in terms of energy. Some
might argue that the hydrocarbon plants have a higher energy value than a
cellulosic plant per unit dry matter. But for our purposes, we can generally
assume that 1 metric ton dry matter is approximately equivalent to 2.4 bbls of
oil. Although estimates will vary in any given study, NAS (1976) suggests that
one ha of water hyacinth can produce more than 70,000 m3 of biogas
(70% methane, 30% CO2). Each kg of dry matter will yield 370 liters biogas
with a heating value of 22,000 KJ/m3 (580 Btu/ft3)
compared to pure methane (895 Btu/ft3) (Curtis and Duke, 1982).
Wolverton and McDonald report only 0.2 m3 methane 7 per kg
indicating requirements of 350 MT biomass/ha to attain the 70,000 m3
yield projected by NAS. Ueki and Kobayashi (1981) expect more than 200
MT/ha/yr. Reddy and Tucker (1983) report experimental maximum of more than a
half ton a day. The liquid sludge is an organic fertilizer with soil
conditioner as a byproduct (Curtis and Duke, 1982). Bengali farmers use dry
water hyacinths as fuel, collecting and piling them up to dry at the onset of
the cold season (C.S.I.R., 1948-1976). The ashes are then used as fertilizer.
In India, a ton of dried water hyacinth yield ca 50 liters ethanol and 200 kg
residual fiber (7,700 Btu). Bacterial fermentation of one ton yields 26,500 cu
ft gas (600 Btu) with 51.6% methane, 25.4% hydrogen, 22.1% CO2, and 1.2%
oxygen. Gasification of one ton dry matter by air and steam at high
temperatures (800°) gives ca 40,000 ft3 (ca 1,100 m3)
natural gas (143 Btu/cu ft?) containing 16.6% H3, 4.8% methane, 21.7% CO, 4.1%
CO2, and 52.8% N. The high moisture content of water hyacinth, adding so much
to handling costs, tends to limit commercial ventures. In arid climates with
natural impoundments, cluttered with water hyacinth, the water might be viewed
positively rather than negatively. Taking advantage of prevailing winds,
collections and processors might be located on an impoundment (perhaps even a
wastewater treatment system). The harvested biomass could be converted to
ethanol, natural gas, even hydrogen and nitrogen (who needs gaseous N),
fertilizer, the byproduct water and fertilizer used to irrigate nearby
cropland. Since waterhyacinth is intolerant of salt, salinization might
eventually jeopardize this venture. Waterhyacinths do not occur in water with
average salanities greater than 15% that of sea water. In brackish water, its
leaves show epinasty and chlorosis, eventually dying. Saltcedars (Tamarix)
might be planted to mine the salts, themselves being used in the production of
fuel and fertilizer (somewhat salty). I'm inclined to agree with Benemann
(1981), "Development of aquatic plant systems for waste treatment and
food-feed-fiber-fuel production may be a prudent investment with a large
potential return...In case of microalgae and water hyacinth, a continuous,
hydraulic production system can be designed. This allows better utilization of
capital investments than in conventional agriculture, which is essentially a
Azotobacter chroococcum, an N-fixing bacteria, may be concentrated
around the bases of the petioles but doesn't fix N unless the plant is
suffering extreme N-deficiency (Matai and Bagchi, 1980). Neochetinia
eichhorniae, imported to Florida from Argentina in 1972, has caused "a
substantial reduction in waterhyacinth production" (in Louisiana) in the form
of reduced plant height, weight, root length, and fewer daughter plants (Goyer
and Stark, 1981).
|DM MT/ha/yr |
|Azolla ||10 |
|Beta ||4.4-11.7 |
|Brassica ||3-10 |
|Casuarina equisetifolia ||8.3 |
|Cichorium intybus ||5.5-7.9 |
|Colocasi esculenta ||9-19 |
|Cynodon dactylon ||23.5-24.6 |
|Daucus carota ||2.5-5.5 |
|Eichornia crassipes ||30-88 |
|Elodea ||3 |
|Eucalyptus ||5.6-20 |
|Helianthus tuberosus ||2.2-9.5 |
|Hydrilia ||15 |
|Hydrocotyle umbellata ||20-58 |
|Ipomoea batatas ||7-23 |
|Lemna ||12 |
|Manihot esculenta || 2-17 |
|Melaleuca quinquenervia ||28.5 |
|Paspalum notatum ||22.4 |
|Pennisetum sp. (Napier) ||57.3 |
|Pinus clausa ||9.0 |
|Pinus elliottii ||9.4 |
|Saccharum ||32-54 |
|Sorghum ||16-37 |
|Sorghum 'Sordan' ||22.4 |
|Typha sp. ||20-40 |
Complete list of references for Duke, Handbook of Energy Crops
- Agriculture Handbook 366. 1970. Selected weeds of the United States. USDA, ARS.
- Benemann, J.R. 1981. Energy from fresh and brackish water aquatic plants. p.
99-121.In: Klass, D.L. (ed.), Biomass as a nonf ossil fuel source. ACS
Symposium Series 144. ACS. Washington. 564 p.
- Curtis, C.R. and Duke, J.A. 1982. An assessment of land biomass and energy
potential for the Republic of Panama. vol. 3. Institute of Energy Conversion.
- C.S.I.R. (Council of Scientific and Industrial Research). 1948-1976. The wealth
of India. 11 vols. New Delhi.
- Duke, J.A. 1981b. The gene revolution. Paper 1. p. 89-150. In: Office of
Technology Assessment, Background papers for innovative biological technologies
for lesser developed countries. USGPO. Washington.
- Duke, J.A. and Wain, K.K. 1981. Medicinal plants of the world. Computer index
with more than 85,000 entries. 3 vols.
- Gohl, B. 1981. Tropical feeds. Feed information summaries and nutritive values.
FAO Animal Production and Health Series 12. FAO, Rome.
- Goyer, R.A. and Stark, J.D. 1981. Suppressing water hyacinth with an imported
weevil. La. Agr. 24(4):4-5.
- Holm, L.G., Plunknett, D.L., Pancho, J.V., and Herberger, J.P. 1977. The
world's worst weeds. Univ. Press of Hawaii. Honolulu.
- Holm, L.G., Pancho, J.V., Herberger, J.P., and Plucknett, D.L. 1979. A
geographical atlas of world weeds. John Wiley & Sons, New York.
- Mara, M.J. 1976. Estimated values for selected water hyacinth by-products.
Econ. Bot. 30:383-387.
- Matai, S. and Bagchi, D.K. 1980. Water hyacinth: a plant with prolific
bioproductivity and photosynthesis. p. 144-148. In: Gnanam, A., Krishnaswamy,
S., and Kahn, J.S. (eds.), Proc. Internat. Symp. on Biol. Applications of Solar
Energy. MacMillan Co. of India, Madras.
- N.A.S. 1976. Making aquatic weeds useful. National Academy of Sciences,
- Perry, L.M. 1980. Medicinal plants of east and southeast Asia. MIT Press,
- Reddy, K.R. and Tucker, J.C. 1983. Productivity and nutrient uptake of water
hyacinth Eichhornia crassipes. 1. Effect of nitrogenous source. Econ.
- Reed, C.F. 1970. Selected weeds of the United States. Ag. Handbook 366. USDA,
- Smith, W.H. and Dowd, M.L. 1981. Biomass production in Florida. J. For.
- Ueki, K. and Kobayashi, T. 1981. Cultivation of new biomass resources. Energy
Develop. in Japan 3(3):285-300.
- Wolverton, B.C. and McDonald, R.C. 1981. Energy from vascular plant wastewater
treatment systems Eichhornia crassipes, Spirodela lemna,
Hydrocotyle ranunculoides, Pueraria lobata, biomass harvested for
fuel production. Econ. Bot. 35(2):224-232.
last update July 9, 1996